1. Field of the Invention
The present invention relates to piloting of commercial aircraft. More particularly, the invention concerns an anti-hijacking system responsive to activation of a panic button aboard the aircraft or by remote override signal to deactivate the pilot""s normal flight controls and program the autopilot system to fly the aircraft to a safe landing.
2. Description of the Related Art
Aircraft hijacking has been a longstanding problem that continues to haunt airlines and the flying public. At best, hijacking merely inconveniences an aircraft""s passengers, flight crew, airline company, and people waiting for the flight to arrive. At worst, hijacking can cause substantial loss of life and property aboard the aircraft and on the ground.
Responding to the ever present threat of hijacking, airports, airlines, and government authorities are implementing different anti-hijacking measures. In airports, numerous measures are taken to screen passengers and their luggage for weapons and dangerous materials. Security personnel oversee service facilities, jet ways, and aircraft parking areas, enforcing security policies that prevent unauthorized persons from entering. Thousands of flights are safely conducted each day, a testament to the implementation or perhaps the deterrent value of these anti-hijacking measures. On rare occasion, though, hijackings still occur.
Guarding against the potential failure of early stage security measures, airlines are using various later stage, on-board anti-hijacking measures. For example, cockpit doors are locked during flight to prevent intrusion by passengers. As another example, some flights carry an armed, plainclothes federal air marshal, specifically trained to stop hijackers. As still another example, when a pilot sets the aircraft transponder to squawk xe2x80x9c7500,xe2x80x9d this alerts air traffic controllers to a hijacking in progress. Still, these measures offer little resistance to a hijacking in progress. Hijackers of sufficient motivation, numbers, brutality, and intimidation can still appear aboard an aircraft despite existing security measures, in which case the flight crew and passengers are utterly helpless. Even when locked, lightweight cockpit doors can be disabled or smashed. Air marshals cannot be present in every flight due to government budget limitations. Although use of the xe2x80x9c7500xe2x80x9d transponder code alerts air traffic controllers to the hijacking, this does nothing to stop a hijacking in progress, and knowledgeable hijackers have been known to disable aircraft transponders.
As shown above, existing measures are not always sufficient to prevent armed hijackers from boarding commercial aircraft. And, once aboard an aircraft, hijackers of sufficient motivation can wreak havoc with little or no meaningful resistance. Few defensive measures are available to deter or inhibit terrorists from achieving their objectives once the aircraft is airborne and the terrorists have assumed control. Clearly, then, the state of the art is plagued with certain unsolved problems that stymie efforts to provide a completely safe flying environment.
The anti-hijacking system of this invention is utilized with aircraft having an autopilot system. This system includes a transceiver to communicate with remote guidance facilities such as ground control or satellite relay. A panic button is provided for flight crew to manually activate the invention""s anti-hijacking measures. A manager is coupled to the transceiver and panic button, as well as existing avionics such as the aircraft""s master computer and autopilot. The invention may also utilize a mechanical or electrical relay, coupled between the pilot controls and the aircraft flight systems.
Initially, the manager waits for an override input such as activation of the panic button or receipt of a predetermined override signal from the remote guidance facilities via the transceiver. Then, responsive to the override input, the manager takes certain counter-hijacking measures, such as taking control of aircraft flight systems, deactivating on-board control of the autopilot system, and programming the autopilot to fly the aircraft to a safe landing. The manager may obtain flight routing and landing instructions from the remote guidance facilities via the transceiver, in which case the manager transmits flight condition data (such as airspeed, altitude, fuel remaining, etc.) to the remote guidance facilities to assist humans or computers in remotely computing the optimal flight path and landing instructions for the aircraft. In another embodiment, the manager determines the optimal flight routing and landing instructions by evaluating nearby airports in view of the aircraft""s position and other preestablished criteria. As an enhancement to the foregoing embodiments, the remote guidance facilities may also transmit manual commands for the manager to individually implement by manipulating the aircraft flight systems. In preparation for possible loss of the aircraft, the manager may additionally assemble and upload flight data recorder and cockpit voice recorder data to the remote guidance facilities via the transceiver.
The foregoing features may be implemented in a number of different forms. For example, the invention may be implemented to provide a method to prevent aircraft hijacking by deactivating pilot controls and forcing the aircraft""s autopilot system to fly the aircraft to a safe landing. In another embodiment, the invention may be implemented to provide an apparatus with hardware components and interconnections assembled and configured to prevent hijacking in this manner. In still another embodiment, the invention may be implemented to provide a signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital data processing apparatus to perform anti-hijacking measures as described herein. Another embodiment concerns logic circuitry having multiple interconnected electrically conductive elements, such elements configured to conduct anti-hijacking operations as described herein.
The invention affords its users with a number of distinct advantages. In general, the invention counteracts otherwise successful hijackings by forcibly assuming control of the aircraft, and overriding pilot controls in the cockpit. This prevents hijackers from flying the aircraft, and also prevents pilots from flying the aircraft according to hijackers"" directions. Also, widespread, public implementation of the invention""s anti-hijacking system deters hijackers by informing them of the difficulty of carrying out a successful hijacking. Another benefit of the invention is its flexibilityxe2x80x94anti-hijacking measures may be initiated locally by personnel aboard the aircraft, or remotely by personnel at the remote guidance facility. In the case where remote personnel assume control of the aircraft, the anti-hijacking system transmits various aircraft condition data to remote personnel to aid them in planning the aircraft""s routing and landing. One optional feature of the invention disables the aircraft""s communications equipment, eliminating any chance for the hijackers to communicate demands or threats to people on the ground. Because of its ability to safely fly and land the aircraft, the invention is also beneficial in the event that the pilots are dead or incapacitated due to hijacking, unforeseen cabin depressurization, midair collision, or any other reason. The invention also provides a number of other advantages and benefits, which should be apparent from the following description of the invention.